Given the increasing popularity of golf and the lack of available courses, golfers tend to practice with specialized equipment which can be used in a yard or other available space. Various types of simulators have been proposed for the purpose of swing practice, that is, forcefully hitting the ball forward. However, rolling the ball or putting practice require only a flat surface covered with suitable carpeting and with a hole or substitute goal. In putting the ball is hit with a club called a putter, with a relatively broad iron whose striking surface is nearly vertical when contacting the ball. The main difficulty in putting is to orient the striking surface of the iron along a plane which is perpendicular to the vertical plane passing through the center of the ball and the through center of the hole. In reality, a golfer can only acquire the habit of orienting the club correctly after numerous repetitive practice strokes, since the direction which the ball takes supplies the only indication of whether the iron position was correct.
Putting practice devices are already known and consist of one or two luminous diodes on the putter head, each emitting a linear beam in a direction perpendicular to the striking surface, thereby allowing the golfer to stop the club in the ideal position. However, such a device is of little use when the club moves, as the line of each light beam on the ground is a point which moves too quickly to be of any use to the player in correcting his or her motions.
U.S. Pat. No. 3,953,034 concern an auxiliary device mounted on a golf club for swing practice. A linear laser light beam emitted by a light source attached to the handle strikes a convex mirror attached below the handle near the striking surface. The laser beam is reflected forward in the form of a planar vertical beam perpendicular to the striking surface, creating a line of light on the ground which predicts the direction parallel to the probable trajectory of the ball. In actuality, such a device allows one to verify only the horizontal orientation of the striking surface and no other parameters relating to its position, notably the possibility that it will diverge laterally from the ball. Furthermore, it is not useful for putting practice when the ball is fairly close to the hole, since the light beam it creates would pass beside the hole and would not give the golfer a clear, precise indication.